Positioning system

ABSTRACT

A positioning system for attachment to a vehicle for operation of a power tool by a ground-based operator sitting in the vehicle provides a telescoping mast attached to the vehicle, a pivot bracket connecting an upper arm to the upper portion of the telescoping mast, mounting means for mounting the power tool on the upper arm; and power means for operating the power tool from the operator&#39;s position in the vehicle.

RELATED APPLICATIONS

This is a continuing application that claims the benefit of the earlierfiling date of application Ser. No. 11/827,485 filed on Jul. 11, 2007.

FIELD

The present embodiments relate generally to positioning a work articleand more particularly, but without limitation, to operably positioningthe work article at elevated work locations.

BACKGROUND

Tree limbs are typically removed by sawing, but most are located higherthan what a person can reach with a hand-held saw while standing on theground. In some previously attempted solutions the person with the sawis lifted by a device, such as a man-lift or a tractor bucket. Thatprocedure is dangerous and usually requires two workers, one to controlthe lifting device and another to operate the saw. Another procedureeven more dangerous is climbing the tree with the saw, such as by tyinga rope to the saw and pulling it up to a perch in the tree. In otherpreviously attempted solutions the person stands on the ground andraises a reciprocating saw attached to the end of a pole, commonlyreferred to as a “pole saw.” However, the height and size of limb thatcan be cut with a pole saw is unacceptably limited.

Improvements are needed in the art that enable a person to safely andefficiently cut large tree limbs that are unreachable from the ground.It is to those improvements that the embodiments of the presentinvention are directed.

SUMMARY OF THE INVENTION

In some embodiments a positioning system attaches to a vehicle foroperation of a power tool by a ground-based operator sitting in thevehicle. The positioning system has a telescoping mast that includes anupper portion and a lower portion. Attachment means attaches the lowerportion of the telescoping mast to the vehicle. A pivot bracket connectsan upper arm to the upper portion of the telescoping mast, the upper armhaving a proximate end adjacent the pivot bracket and a distal enddistal from the pivot bracket. Mounting means is provided to mount thepower tool to the distal end of the upper arm. Power means is providedfor operating the power tool from the operator's position in thevehicle.

In some embodiments an apparatus is provided that has a mast, and an armjoined to the mast by a pivot connection. A power tool is supported bythe arm, and a flexible strap connects the arm to the mast to limitarticulation of the arm in a first rotational direction when theflexible strap is taut.

In some embodiments an apparatus is provided that has a powered chainsaw supported by an arm that is articulated around the end of anextension mast, and means for controlling the articulation of the armthat gives a visual indication of the suitability of a feed rate withwhich the powered chain saw is being operably advanced in cutting anarticle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a positioning system constructed in accordance with thepresent embodiments and attached to a tractor.

FIG. 2 is an enlarged depiction of the positioning system of FIG. 1.

FIG. 2A depicts a receiver member attached to the bucket of the tractorfor operably supporting the positioning system of the presentembodiments.

FIG. 2B is an enlarged depiction of a positioning system constructed inaccordance with embodiments of the present invention.

FIG. 3 depicts a portion of the positioning system of FIG. 2B.

FIG. 3A is similar to FIG. 3 but depicting the saw making initialcontact with the limb.

FIG. 3B is similar to FIG. 3A but depicting the saw cutting at a properfeed rate.

FIG. 3C is similar to FIG. 3A but depicting the saw cutting at too slowof a feed rate.

FIG. 3D is similar to FIG. 3A but depicting the saw cutting at too fastof a feed rate.

FIG. 4 depicts the opposing side of the positioning system of FIG. 2.

FIG. 5 depicts a positioning system that is constructed in accordancewith embodiments of the present invention.

FIG. 6 is a partially cut away depiction of the upper arm of thepositioning system of FIG. 4.

FIG. 6 a is similar to FIG. 6 but depicting a lubrication system thatdiverts a portion of the hydraulic fluid to lubricate the chain bar andthe cutting chain.

FIG. 7 depicts the positioning system of FIGS. 1-6 wherein the upper armis moveable between an operable position depicted in broken lines and aninoperable folded position for safe transit depicted in solid lines.

FIG. 7A is similar to a portion of FIG. 7 but depicting a locking pininserted to fix the positioning system in the folded position.

FIG. 7B depicts the locking pin inserted to provide a positive stoplimiting the upward articulation of the saw.

FIG. 7C is an enlarged detail of the locking pin of FIG. 7B.

FIG. 8 depicts a positioning system that is constructed in accordancewith embodiments of the present invention.

FIG. 9 depicts a positioning system similar to that depicted in FIG. 7but constructed in accordance with other embodiments of the presentinvention.

FIG. 10 is an exploded depiction of portions of the operable attachmentof the chain saw to the upper bar.

FIG. 10A depicts an elevational view of the shaft adapter that mounts tothe motor output shaft and operably supports the chain drive sprocket ofFIG. 10.

FIG. 10B depicts a cross sectional view of the shaft adapter of FIG.10A.

FIG. 11 depicts an enlarged view of a spacer block with oiling grooves.

FIG. 12 depicts a positioning system that is constructed in accordancewith embodiments of the present invention.

FIG. 13 depicts the positioning system of FIG. 12 at a differentoperable position.

FIG. 14 depicts a detailed enlarged view of the automatic oiler in thepositioning system of FIGS. 12-13.

FIG. 15 depicts another view of the automatic oiler in the positioningsystem of FIGS. 12-13.

FIG. 16 depicts a positioning system that is constructed with upper armlateral pivotal movement in accordance with embodiments of the presentinvention.

FIG. 17 depicts a nozzle mounted on the end of the upper arm.

FIG. 18 depicts a positioning system that is constructed with lateralpivotal movement of the lower end of the mast in accordance withembodiments of the present invention.

FIG. 19 depicts the positioning system of FIG. 18 attached to a tractorbucket.

DETAILED DESCRIPTION

The embodiments of the present invention as described herein generallycontemplate a positioning system for attachment to a vehicle foroperation of a power tool by a ground-based operator in the vehicle. Thepositioning system contemplates enabling one person to operate the powertool remotely, such as at elevated location. The embodiments describedare predominantly directed to the operation of a chain saw, although thecontemplated embodiments are not so limited. Operating a chain sawproperly requires presenting the cutting chain to the tree limb at afeed rate that is conducive to effective cutting. Either advancing thecutting chain too fast or too slow not only diminishes the cuttingefficiency but also causes unnecessary wear and tear on the chain saw.

The skilled artisan knows that there is a tactile response that one getsfrom holding a chain saw while cutting that informs the operator as tothe proper feed rate with which the chain saw should be advancingthrough the limb. Basically, if the chain saw is in proper mechanicalcondition then the operator essentially only needs to guide thedirection of the cut, allowing the weight of the chain saw itself toestablish the cutting feed rate. That tactile response is lost whenusing the chain saw when it is supported at the distal end of anextension pole. If the extension pole is operably guided by a liftingdevice, such as a tractor bucket, then it is easy to apply too muchforce in advancing the chain saw, causing damage to the chain saw orexceeding a hydraulic system pressure bypass limit. In somecircumstances, exceeding the bypass limit can create a potentiallydangerous condition by losing positioning control of a running chainsaw. That could cause the saw to drop and contact a hazard or otherobject below.

Some embodiments discussed below are particularly directed to providinga visual indicator response to the operator that informs her that theproper feed rate is being applied by her lowering of the tractor bucketduring cutting, in order to replace the lost tactile response.

Referring generally to the drawings and more particularly to FIG. 1, apositioning system 50 has a telescoping mast assembly 52 and an upperarm 54 supported by the telescoping mast assembly 52. The telescopingmast assembly 52 has a lower end portion 56 and an upper end portion 58.The lower end portion 56 is removably attachable to the bucket “B” of atractor “T.” The upper arm has a proximate end 60 and a distal end 62.The proximate end 60 of the upper arm 54 is pivotally attached to theupper end portion 58 of the telescoping mast assembly 52. A mountingplate 64 attached to the distal end 62 of the upper arm 54 by bolts 63,65 (FIG. 2) supports a chain saw assembly 66. Thus, the tractor operatorcan raise the loader bucket B of the tractor T to position the chain sawassembly 66 above a tree limb L that has been selected for cutting, andthen lower the bucket B to control the cutting feed rate of the chainsaw.

Referring now to FIGS. 2 and 4, the telescoping mast assembly 52 of thepositioning system 50 consists of an outer mounting member 68 and aslidably extending inner member 70. Preferably, the outer mountingmember 68 is constructed of square tubing, and the inner member 70 isconstructed of and I-beam. Orienting the I-beam flanges of the innermember 70 to straddle the welded seam of the outer member 68 providesfor an acceptable sliding engagement therebetween. The outer mountingmember 68 has bores 72, 78 that are sized for passing bolts therethroughfor attaching the outer mounting member 68 to the tractor bucket B.

Alternatively, FIG. 2A depicts a receiver member 69 attached to thetractor bucket B for a more convenient fastener-less attachment of theouter mounting member 68 to the tractor bucket B. The receiver member 69is attached to the tractor bucket B with a plurality of fasteners 71,such as but not limited to the four-fastener pattern depicted. Thereceiver member 69 defines a passage 73 that is open on one end andsized to receivingly engage the outer mounting member 68. The passage 73is closed on the other end (not shown) to limit the insertion depth. Thereceiver member 69 can thus advantageously be left in place on thetractor bucket B, and the outer mounting member 68 can then quickly beinserted into the receiver member 69 for operably supporting thepositioning system 50. Preferably, the receiver member 69 is mounted tothe tractor bucket B in an unobtrusive location, such to the backside ofthe tractor bucket B as depicted, so that it does not encumber otherusage of the tractor.

Returning to FIG. 2, a locking pin bore 76 in the outer mounting member68 is alignable with a selected one of a plurality of bores 80, 82, 84,86, 88, 90 in the inner member 70. A locking pin 92 is depicted as beingplaced through the locking pin bore 76 and the bore 88 to fix thetelescoping mast assembly 52 at a desired length.

FIG. 2B depicts another positioning system 50′ that employs a solidunitarily constructed mast 53 instead of the telescoping mast assembly52 of FIG. 2. Other modifications in the embodiments depicted in FIG. 2Bare described below in reference to FIGS. 3 and 3A-3C.

Still referring to FIGS. 2 and 4, the proximate end 60 of the upper arm54 is affixed to a pivot bracket 94 which is, in turn, pivotallyattached to the upper end portion 58 of the telescoping mast assembly52, such as by a pivot bolt 96. A mounting bracket 98 attached to theinner member 70 supports one end of an extensible cylinder 100, such asa hydraulic cylinder. The other end of the hydraulic cylinder 100 isattached to the pivot bracket 94, such as via a bolt 102. Hydrauliclines 104, 106 (FIG. 5) provide supply and return lines for operatingthe hydraulic cylinder 100. The linear movement of the hydrauliccylinder 100 articulates the chain saw assembly 66 along an arcuate pathrepresented by the double-headed arrow and denoted by the referencenumber 110.

The embodiments depicted in FIG. 2 are illustrative and not limiting ofthe various contemplated ways of telescopingly adjusting the length ofthe telescoping mast assembly 52. In alternative equivalent embodiments,for example, a winch can be mounted to the lower end of the outer member68 and aligned with a sheave mounted at the distal (upper) end of theouter member 68. A cable can be extended from the winch, trained aroundthe sheave, and attached to the lower end of the inner member 70. Thus,the weight of the inner member 70 and the saw assembly 66 it supports iscountered by the taut cable, which can be let out or taken up by thewinch to lower and raise the inner member 70, respectively.

Still referring to FIGS. 2 and 4, the mounting plate 64 attached to thedistal end 62 of the upper arm 54 supports the chain saw assembly 66. Achain drive sprocket 112 driven by an output shaft 114 of a hydraulicmotor 116 is aligned with a chain bar 118 having elongated slots 120,122 (FIG. 10) for tension adjustment. A cutting chain 124 having cuttingelements incorporated therein is trained around the chain drive sprocket112 and the chain bar 118. The chain bar 118 can be selectivelypositioned with respect to the chain drive sprocket 112 to impart adesired tension on the cutting chain 124. Bolts 126, 128 (FIG. 10) aretightened to hold a desired cutting chain tension. Hydraulic lines 144,146 provide supply and return lines, respectively, from a hydraulicpower source to turn the motor 116 and, in turn, rotate the output shaft114. An oil line 148 provides gravity feed of oil from an oil reservoir(See FIG. 6) to the cutting chain 124.

FIG. 3 depicts embodiments of the present invention whereby thehydraulic cylinder 100 is replaced with a flexible strap 152 forcontrolling the articulation of the chain saw assembly 66. The strap 152provides the user with a visual indicator of the correct feed rate atwhich the cutting chain 124 is being presented to the tree limb beingcut, as described in detail below. Because the strap functions as avisual indicator, it is preferably constructed from a high-visibilitycolored material, such as yellow or orange. The strap 152 can beconstructed of a suitably strong material such as a nylon fabric, oralternatively constructed of materials such as but not limited to cableor chain.

The optimal feedrate for presenting the cutting chain 124 to the treelimb is provided by the force of gravity alone acting on the weight ofthe chain saw assembly 66 and the supporting structure of the upper arm54. However, the user loses all tactile sensation during the cuttingaction by virtue of the chain saw assembly 66 being remotely supportedat the distal end of the positioning system 50. FIG. 3 depicts theresting, inoperable position of the chain saw assembly 66, where thefull weight of the chain saw assembly 66 and upper bar 54 urges thecutting chain 124 downward (as viewed in FIG. 3) and as such the strap152 is taut. This is the state of the strap 152 that the user wouldexpect to see while moving the bucket B to initially position the chainsaw assembly 66 over and then downwardly toward the tree limb that isgoing to be cut.

The operator monitors the taut state of the strap 152 while lowering thetractor bucket B to advance the cutting chain 124 toward the tree limb125. FIG. 3A depicts a visual indicator provided by the strap 152 at themoment that contact is made with the tree limb. Particularly, at thatmoment the visual indication of the strap 152 changes from being taut tobeing just slightly slack. This transition of the strap 152 visualindicator is effectively magnified if there is any wind present, becausein a mild wind the taut strap 152 of FIG. 3 remains rigid whereas theslightly slack strap of FIG. 3A will flap slightly in the wind. Evenwithout the aid of wind, however, this first visual indication from tautto slightly slack is clearly noticeable when the strap 152 loses itsrigid form that is characteristic of the taut state.

Once contact is made, the operator then aims to lower the tractor bucketB at a rate that maintains the slightly slack state of the strap 152 asthe cutting chain 124 progressively cuts through the tree limb 125, asdepicted in FIG. 3B. That is, if after beginning to cut into the treelimb 125 the strap 152 goes taut again, as depicted by FIG. 3C, thenthat is a visual indication that the bucket B speed is too slow becausethe cutting chain 124 has presently cut away all the tree limb materialunder it; hence, the cutting action is starved because feedrate is tooslow.

However, on the other hand if the tractor bucket B is being lowered toofast then the visual indication of the strap 152 will change from beingjust slightly slack to being highly slack, as depicted in FIG. 3D. Ahighly slack strap 152 essentially hangs limp and assumes a pronouncedarcuate shape in the lack of wind, and in a wind noticeably flaps morethan in the slightly slack state. The highly slack state indicates thatthe downward force acting on the cutting chain 124 is greater than thatprovided merely by the weight of the chain saw assembly 66 and upper arm54; the cutting action is overwhelmed because the feedrate is too fast.

Referring now to FIG. 5, another positioning system 250 according to thepresent embodiments includes a telescoping mast hydraulic cylinder 252attached at one end to a bracket 254 that is, in turn, attached to theouter mounting member 68 of the telescoping mast assembly 52. The otherend of the hydraulic cylinder 252 is attached to a bracket 256 that is,in turn, attached to the slidably extendable inner member 70 of thetelescoping mast assembly 52. Hydraulic lines 258, 260 connect thehydraulic cylinder 252 to a hydraulic power source (not shown) such asfrom the tractor T. The positioning system 250 shown in FIG. 5 permitshydraulic control of both the length of the telescoping mast assembly52, by positioning the hydraulic cylinder 252, and of articulation ofthe chain saw assembly 66, by positioning the hydraulic cylinder 100.Preferably, the hydraulics system powering the hydraulic cylinder 252can provide the necessary pressure and then hold that pressure tomaintain a corresponding desired length of the telescoping mast assembly52 without the use of a locking pin 92 (FIG. 2).

Referring now to FIG. 6, in these illustrative embodiments the upper arm54 of the positioning system 50 can contain an oil reservoir 270. Avented cap 272 extends through a bore 274 in the upper arm 54 to engagea bore 276 in the oil reservoir 270. A fitting 278 in the oil reservoir270 fluidly communicates oil from the oil reservoir 270 to the oil line148, and the oil flows through the oil line 148 to another fitting 280that operably delivers the oil to the cutting chain 124.

In this manner, the oil from the oil reservoir 270 is gravity fedthrough the oil line 148 when the chain saw assembly 66 articulatesdownwardly while cutting the tree limb L, as depicted in FIG. 1. The oilreservoir 270 can be secured within the upper arm 54 by its connectionto the cap 272. The cap 272 has a removable cover to permit filling theoil reservoir 270 while it remains secured inside the upper arm 54.Although the illustrative embodiments depict the upper arm 54 and thechain oil reservoir 270 both having a square cross-section, the presentembodiments are not so limited.

Alternatively, FIG. 6A depicts embodiments wherein the oil line 148 isconnected to the hydraulic supply line 144. A three-way fitting 147connects the supply line 144 to the motor 116. A flow control valve 149is also connected to the three-way fitting 147 to fluidly communicate aportion of the supply-side hydraulic fluid to the oil line 148 forlubricating the chain bar 118 and the cutting chain 124. Preferably, theflow control valve 149 is adjustable, such as a needle valve, fordelivering a selected amount of lubrication. The flow control valve 149also preferably has a check valve component to it to prevent loss ofhydraulic fluid when the saw is not being operated. A valve that hasbeen used successfully is one manufactured by Alkon Corporation ofFremont, Ohio, and marketed as model JF2.

Referring now to FIG. 7, detachment of the hydraulic cylinder 100 of thepositioning system 50, 250, or disconnection of one end of the limitstrap 152 of the positioning system 50′, permits the upper arm 54 topivot on the pivot bolt 96 so the upper arm 54, the mounting plate 64,and the saw assembly 66 can articulate along an arc 294 between anextended use position (shown in phantom) and a folded storage position.

FIG. 7A is an enlarged view of a folded positioning system 50′ similarto that depicted in FIG. 7 but having two holes 95, 97 in the pivotbracket 94 that are sized to receive a locking pin 99. In the foldedarrangement depicted, the hole 97 aligns with another hole 101 (FIG. 7B)in the mast 53 so that insertion of the locking pin 99 affixes the mast53 and the arm 54 together.

In FIG. 7B the locking pin 99 has been removed from the hole 97 andinserted in the other hole 95. The strap 152 is connected to support theupper arm 54 in an operable position. FIG. 7C best depicts how thelocking pin 99 in the hole 95 provides a positive stop that abuttinglyengages against the mast 53 to limit the upward articulation of theupper arm 54.

Referring now to FIG. 8, another positioning system 350 has atelescoping upper arm 354 consisting of a telescoping upper arm outermember 356 and a slidably extending inner member 358 for selectivelylengthening the upper arm 354. A hydraulic cylinder 360 is attached atone end to a bracket 362 on the outer member 356. The other end of thehydraulic cylinder 360 is attached to a bracket 364 on the slidablyextending inner member 358. Hydraulic lines 366, 368 connect thehydraulic cylinder 360 to a hydraulic power source (not shown) such asfrom the tractor T.

Referring now to FIG. 9, another positioning system 450 is similar tothe positioning system 50 shown in FIG. 7 except for a longitudinallyaligned orientation of the pivot bracket 94, the upper arm 54, themounting plate 64, and the chain bar 118 along a common longitudinalaxis 452. This permits a more compact folded arrangement.

Referring now to FIGS. 10 and 11, the mounting plate 64 is attached nearthe distal end 62 of the upper arm 54 by bolts 552, 554 disposed throughbores 556, 558, respectively in the mounting plate 64, through bores560, 562, respectively near the distal end of the upper arm 54, andsecured by nuts 564, 566, respectively. As previously discussed, themounting plate 64 is thus attached to the distal end 62 of the upper arm54 and supports, in turn, the chain saw assembly 66.

FIGS. 10A and 10B depict side and cross sectional views, respectively,of a shaft adapter 111 that is constructed in accordance withembodiments of the present invention. The shaft adapter 111 mountsdirectly to the output shaft 114 of the motor 116, and drivingly engagesa chain drive sprocket 112 (FIG. 10) that engages and drives the cuttingchain 124. The shaft adapter 111 defines a bore 113 and keyway 115 thatcooperatively form a close mating relationship with the keyed outputshaft 114 (FIG. 10) of the motor 116. A number of spaced protuberantteeth 117 circumscribing the outer surface are sized and spaced tomatingly engage a spline pattern defined in a mounting bore of the chaindrive sprocket 112. A chamfer 119 is formed at both ends of the bore 113to enhance the penetration of a weld that is used to attach the shaftadapter 111 to the shaft 114. A pair of slots 121 circumscribe the teeth117 and are each sized to operably receive a snap ring.

The shaft adapter 111 is keyed and welded to the motor shaft 114 and, inturn, drives the chain drive sprocket 112 via an engagement therewiththe teeth 117. This eliminates any need for a set screw attachment,which can vibrate loose during cutting. The chain bar 118 (FIG. 10) hasa peripheral edge that defines a slot sized to retain the cutting chain124 as it is rotated. The chain drive sprocket 112 is operably capturedbetween the snap rings supported in the slots 121 to maintain itsalignment with the cutting chain 124. Preferably, the shaft adapter 111is mounted on the shaft 114 so as to align the center of the spacingbetween the slots 121 with the peripheral edge of the chain bar 118.

In the manner described above, the chain drive sprocket 112 is driven bythe shaft 114 of the hydraulic motor 116, and is aligned with the chainbar 118 having elongated slots 120, 122 for adjusting the tension of thecutting chain 124. The chain drive sprocket 112, in turn, drives thecutting chain 124. The position of the chain blade 118 with respect tothe chain drive sprocket 112 determines the tension on the chain 124.Bolts 126, 128 extending through bores 130, 132 in the locking plate134, through the elongated slots 120, 122 in the chain bar 118, andthrough bores 136, 138 in the mounting plate 64 are secured by nuts 140,142. Hydraulic lines 144, 146 connect the hydraulic motor 116 to ahydraulic power source (not shown) such as from the tractor T.

Still referring to FIGS. 10 and 11, the spacer 282 is held between thechain bar 118 and the mounting plate 64 by bolts 126, 128 secured inplace by nuts 140, 142, respectively. The spacer 282 includes oilingchannels 284, 286 on one side and like oiling channels (not shown) onthe other side. The oiling channels 284, 286 communicate chain oil fromthe fitting 280 (FIG. 6) to the chain bar 118 and the cutting chain 124.Bores 582, 584 in the spacer 282 fluidly connect oiling channels onopposite sides of the spacer 282. Bores 586, 588 receive bolts 126, 128,respectively for attachment of the chain bar 118 to the mounting plate64.

Referring now to FIGS. 12-15, another positioning system 550 accordingto the present embodiments includes an oil reservoir 570 within theupper arm 54. An unvented cap 572 extends through a bore 574 in theupper arm 54 to engage a bore 576 in the oil reservoir 570. A pumpassembly 580 automatically pumps oil from the oil reservoir 570 to thefitting 280 each time the chain saw assembly 66 is articulateddownwardly. An actuating member 578 attached to the upper end of thetelescoping mast assembly 52 contacts a spring-biased open piston 582 influid communication with a cylinder 583. A suction check valve 584fluidly connecting the cylinder 583 to the oil reservoir 570 preventsoil from flowing from the cylinder 583 into the oil reservoir 570, whilea discharge check valve 586 permits oil to flow through the oil line 148to the fitting 280.

Still referring to FIGS. 12-15 and more particularly to FIG. 13, whenthe force on the actuating member 578 is relieved, a spring 588 affectsa suction stroke. Chain oil is prevented from flowing back through thedischarge check valve 586 into the cylinder 583, so chain oil is drawninto the cylinder 583 through the suction check valve 584. When theupper arm 54 is once again articulated downwardly, the pump assembly 580once again delivers oil to the fitting 280.

Although in the foregoing illustrative embodiments the chain sawassembly 66 is powered by a hydraulic motor, in alternative equivalentembodiments the chain saw assembly 66 can be powered by other powerplants such as but not limited to a pneumatic motor and an electricmotor. Similarly, pneumatic positioners can be used in place of thehydraulic cylinders 100, 252 in alternative equivalent embodiments ofthe present invention.

Referring now to FIG. 16, a top view of another positioning system 650has a vertical pivot bolt 652 operably disposed in vertical bores nearthe distal end 62 of the upper arm 54 and through aligned vertical boresin mating horizontal tabs 656 secured to the mounting plate 64. Ahydraulic cylinder 658 is attached on one end to a bracket 660 on theupper arm 54 and on the other end to a bracket 662 on one of thehorizontal tabs 656. Hydraulic lines 664, 666 connect the hydrauliccylinder 658 to a hydraulic power source (not shown) such as from thetractor T. Linear extension of the hydraulic cylinder 658 alongreference direction 668 causes the mounting plate 64 and, in turn, thechain saw assembly 66 to articulate laterally along the reference arrow670.

Referring now to FIG. 17, the positioning system 650 shown in FIG. 16provides positioning of a nozzle assembly 680 connected to a supply hose682. The supply hose 682 may provide air for thinning fruit, anappropriate chemical mixture for spraying trees and other plant life, orpaint for use on difficult-to-reach locations. A collar 684 secures thenozzle assembly 680 to an adaptor 686.

Referring now to FIGS. 18 and 19, a lateral adjustment system 750 isshown mounted in inner bottom 752 of the tractor bucket B. A four-pointlinkage assembly 760 is formed by a horizontal base 762, parallelvertical members 764, 766 of equal length, and a horizontal top 768. Thehorizontal base 762 consists of two parallel L-shaped members 770, 772secured to the inner bottom 752 of the bucket B by bolts 774 and nuts776. One end of the vertical member 764 is pivotally attached to thehorizontal base 762 by a left bottom pivot bolt 778, and one end of theparallel vertical member 766 is pivotally attached to the horizontalbase 762 by a right bottom pivot bolt 780. The horizontal top 768consists of two parallel L-shaped members 782, 784. The other end of thevertical member 764 is pivotally attached to the horizontal top 768 by aleft top pivot bolt 786, and the other end of the vertical member 766 isattached to the horizontal top 768 by a right top pivot bolt 788. Ahydraulic cylinder 790 is attached at one end to a mounting tab 792attached to the horizontal base 762. The other end of the hydrauliccylinder 790 is attached to a mounting tab 794 located on the inside ofthe vertical member 766. The telescoping mast assembly 52 is attached toa middle portion 796 of the horizontal top 768. Movement of thehydraulic cylinder 790 along direction reference 798 causes thetelescoping mast assembly 52 to move responsively along directionreference 800 while maintaining the telescoping mast assembly 52perpendicular to the horizontal top 768.

The present embodiments have been described as being adaptable for usewith a variety of ground-based vehicles to which the telescoping mastassembly 52 is attached, but the embodiments are not so limited. Inalternative equivalent embodiments the telescoping mast assembly 52 canbe attached to other vehicles such as an upstanding sidewall of a pickupbed, to a bale spike frame, to a skid loader, to a backhoe, to an ATV,and the like. Although some of these vehicles may not contain ahydraulic power source, an auxiliary power source or an alternative typeof power source such as an air compressor with pneumatic embodiments canbe used.

Additionally, the present embodiments have been described as beingadaptable for use in positioning a powered chain saw, but theembodiments are not so limited. In alternative equivalent embodiments avariety of other work articles can be positioned in hard-to-reachelevated locations.

The foregoing description of embodiments of the present invention havebeen presented for purposes of illustration and description. Thedescription does not limit the contemplated embodiments to the formsdisclosed, and many modifications and variations are possible in lightof the description. The embodiments were chosen and described in orderto best explain the principles of the embodiments of the invention, tothereby enable others skilled in the art to understand the variousembodiments with various modifications as are suited to the particularuse contemplated.

What is claimed:
 1. A positioning system for attachment to a vehicle foroperation of a power tool having a cutting edge for cutting a severablemember by a ground-based operator sitting in the vehicle, thepositioning system comprising: a mast having an upper portion and alower portion; attachment means for attaching the lower portion of thetelescoping mast to the vehicle; an upper arm having a proximate anddistal end; a pivot means connecting the proximate end of the upper armto the upper portion of the mast for free pivotal movement of the upperarm relative to the mast between predetermined limits; means formounting the power tool to the distal end of the upper arm; power meansfor operating the power tool from the operator's position in thevehicle; and means for limiting pivotal movement of the upper arm aboutthe pivot means whereby the tool cutting edge rests on the severablemember without added downward pressure during retraction of the mast andwhereby the cutting edge self feeds when the power tool is energized bythe operator.
 2. An apparatus comprising: a mast; an arm joined to themast by a pivot connection; a power tool supported by the arm; and aflexible strap connecting the arm to the mast to limit articulation ofthe arm in a first rotational direction when the flexible strap is taut.3. The apparatus of claim 2 wherein the pivot connection comprises anabutment member that abuttingly engages the mast to limit articulationof the arm in a second rotational direction that is opposite the firstrotational direction.
 4. The apparatus of claim 2 wherein the flexiblestrap comprises a high visibility material.
 5. The apparatus of claim 2further comprising a receiver member that is attachable to a vehicle,the receiver member defining a passage that is sized to receivinglyengage a proximal end of the mast in a close mating relationship tooperably support the apparatus during motion of the vehicle.
 6. Theapparatus of claim 2 wherein the mast comprises an outer member and atelescopingly adjustable inner member.
 7. The apparatus of claim 2wherein the power tool comprises a hydraulically powered component and acutting member, and wherein a portion of a hydraulic fluid supplied topower the hydraulically powered component is selectively diverted tolubricate the cutting member.
 8. The apparatus of claim 7 wherein thehydraulically powered component and cutting member are constituentcomponents in a chain saw.
 9. The apparatus of claim 8 wherein the motorcomprises an output shaft, wherein a chain drive sprocket is welded tothe output shaft to fix them together in operable rotation.
 10. Theapparatus of claim 3 wherein the pivot connection comprises a pivotbracket supporting the arm and pivotally connected to the mast, thepivot bracket defining a first opening that is sized for removableinsertion of the abutment member.
 11. The apparatus of claim 10 whereinthe pivot bracket defines a second opening, the flexible strap isremovably connectable between the pivot bracket and the mast, and whenthe flexible strap is disconnected the arm is rotatable to an inoperablefolded arrangement where the second opening aligns with a third openingdefined by the mast, the second and third openings sized to receive alocking member to affix the arm and the mast together in the inoperablefolded arrangement.
 12. The apparatus of claim 10 wherein the pivotbracket defines a second opening, the flexible strap is removablyconnectable between the pivot bracket and the mast, and when theflexible strap is disconnected the arm is rotatable to an inoperablefolded arrangement where the second opening aligns with a third openingdefined by the mast, the second and third openings sized to receive theabutment member to affix the arm and the mast together in the inoperablefolded arrangement.
 13. An apparatus comprising: a powered chain sawsupported by an arm that is articulated around the end of an extensionmast; and means for controlling the articulation of the arm that gives avisual indication of the suitability of a feedrate with which thepowered chain saw is being operably advanced in cutting an article.